The cases come from Michigan, Ohio, Kentucky, and Tennessee. In the Michigan case, a lesbian couple hopes the appeals court will uphold a decision that struck down the same-sex marriage ban as a violation of equal protection and due process rights.

If they win, April DeBoer and Jayne Rowse say they'll get married and jointly adopt the children they're raising together.

Michigan is first on the docket, followed by the three other states.

Nationwide, there are challenges pending to same-sex marriage bans in more than half the states. And Utah just asked the US Supreme Court to hear a challenge to a lower court ruling that struck down its ban.

Last summer, the Supreme Court granted federal recognition to gay and lesbian married couples.